This invention relates, to a data recording and/or reproducing device for recording and/or reproducing data on or from a recording medium. The present invention also relates to such recording medium.
An illustrative example of the conventional data recording and/or reproducing device is shown in FIG. 1. The device shown in FIG. 1 is a device for converting and companding music signals into digital data for recording and/or reproduction.
The conventional data recording and/or reproducing device 200, shown in FIG. 1, has a central processing unit (CPU) 101 for controlling the system of the device in its entirety, a random access memory (RAM) for the system 104 and a read-only memory (ROM) for the system 103.
A digital signal processor (DSP) 102 is used for executing arithmetic and logical operations for signals, while a signal processing ROM 105 and a signal processing RAM 106 are used for executing arithmetic and logical operation for signals in the DSP 102. In the signal processing ROM 105, there are pre-recorded instruction data for encoding and instruction data for decoding.
In the present data recording and/or reproducing device 200, a data read/write unit 107 writes and reads data between it and a recording medium 199, while a D/A converter 110 converts digital music data into corresponding analog music signals to output the resulting analog music signals to an audio output 108. An A/D converter 111 converts analog music signals entered at an analog,input 109 into digital music data.
Interfacing between the user and the data recording and/or reproducing device 200 is accomplished by using a display unit 112 and a command input unit 113.
With the above-described device, recording/replay of music signals is performed in the following manner.
In recording, analog music signals, entered at an analog input unit 109, are converted by the A/D converter 111 into digital music data, which is compression-encoded by the DSP 102 in accordance with encoding instruction data written in the signal processing ROM 105 and is subsequently recorded on the recording medium 199 via the data read/write unit 107.
In replay, the compression-encoded data is read by the data read/write unit 107 from the recording medium 199 on which the compression-encoded data is pre-recorded. The compression-encoded data thus read is decoded by the DSP 102 in accordance with decoding instruction data written in the signal processing ROM 105. The decoded data is then converted by the D/A converter 110 into analog signals which are outputted at an audio output 108 as replay tousle signals.
Thus the digital music data can be processed only encoding instructions previously stored in the system, and can be reproduced only in a system having decoding instructions capable of reproducing the digital music data.
Consequently, although the recording/reproducing device has hardware capable of satisfactorily executing encoding or decoding instructions other than those stored thereby, it is only possible with the device to record data in accordance with its own stored set of encoding instructions, while data processed with the decoding instructions other than those stored therein cannot be reproduced even although the device can read the data. That is, encoding/ decoding can be made only with software previously stored in the device.
In the current status of the art, the recording medium itself is adapted to accommodate new equipment or hardware is specially designed for a specific recording medium. That is, interchangeablity is assumed not to be provided from the outset. Consequently, no particular problem exists even if the recording medium was recorded on by a device of an inconvenient system or with an old-fashioned device that cannot be reproduced by a new device.
The above-described status of the art favors the sale of a recording medium in which popular material is pre-recorded or a product employing a high performance or multi-functional system because of the possible differentiation from other conventional media or products.
However, if it is desired to purchase an popular music source processed by a plurality of processing systems, it is not possible for the software to accommodate the music source even though the properties of the device itself or the hardware are capable of executing the new processing systems, with the result that the user is obliged to purchase appropriate equipment capable of accommodating these new processing systems.
Recently, it as become popular to employ a recording medium from which the recorded data may be read by a comparatively simple operation, such as an IC card. However, in view of the current status of the art in which the processing by the device itself is executed by the DSP based on the stored program, it happens that, even though the device is capable of writing and reading the recorded data and recording and/or reproducing the data the recording/reproduction cannot be accomplished solely because of the difference in the data processing system.
For solving the above-mentioned difficulties, it may be contemplated to provide the new devices with encoding or decoding instructions of the previous systems or inconvenient systems or to translate data recorded by the inconvenient system or the old-fashioned systems. However, if the new devices are to be equipped with the inconvenient systems or past encoding or decoding instructions, the device tends to suffer from increased redundancy. Besides, the data recorded in the past may be converted into data conforming to the new system only by a laborious converting operation with the risk of deterioration in the sound quality.